Repairing Chimney Flashing

If you have a leaky chimney it’s not always easy to figure out the cause of the leak. We have noticed that in many cases, faulty or bent chimney flashing is the cause of the leak. Chimney flashing is a metal joint that is located at the base of the chimney on the exterior. When the flashing is installed correctly, a watertight seal is formed so that water can’t enter from underneath the flashing. But like everything else, over time the weather corrodes the flashing reducing its overall effectiveness. When American Fireplace technicians perform an annual chimney inspection; we always check to ensure that the flashing is tightly sealed.

Chimney flashing is installed by joining two metal panel parts. The base flashing is the first part and is installed underneath a shingle and bent upward against a masonry chimney. This part of the chimney flashing takes a beating from the weather and it’s in this metal part that we find cracks and holes.

After the base flashing is installed, the counter flashing is installed over the base flashing onto the chimney mortar joint. High-quality urethane caulking should be applied, to complete the job so that it’s waterproof. If the chimney flashing was correctly installed and the caulking has just worn down, we just will add more caulking. It’s when the flashing materials are not installed correctly leaving spaces between the base and the counter flashing will require more extensive repairs. In those cases we will replace the chimney flashing altogether.

Different weather requires different chimney flashing materials. In Houston, we tend to use galvanized steel and aluminum for chimney flashing installation, although we will use copper when we have a little more budget. It’s more durable and the corners can be soldered for an even stronger bond.

Leaks from corroded metal or improper chimney flashing installation don’t always appear immediately. Moisture shows up on the ceiling or in the attic causing the wooden beams and drywall to rot. You’ll usually notice staining on the wall and ceiling after it rains. It doesn’t take long for a small leak to turn into a big problem.

That’s where we come in. American Fireplace has been installing, repairing and cleaning chimneys and fireplaces for more than 20 years. There isn’t a water leak problem that we haven’t been able to solve over this time. That’s why when customers tell us that they have a leaky chimney, it’s important that we perform a water test before the problem is diagnosed and any work is undertaken. Even the most experienced chimney technician will have difficulties pinpointing the point of entry for water. American Fireplace, We Care about Your Air!